Internal-combustion motor.



J. A. SEYMOUR.

INTERNAL COMBUSTION MOTOR.

APPLICATION FILED JUNE 14. 1913.

Patented Mar. 14, 1916.

5 W00 ntoz JAMES ALWARD SEYMOUR, OF AUBURN, NEW YORK.

INTERNAL-COMBUSTION MOTOR.

Specification of Letters Patent.

Patented Mair. Ml, 1916.

Application filed .Tune 14, 1913. Serial No; 773,598.

To all whom it may concern:

Be it known that I, JAMES ALWARD SEY- MOUR, a citizen of the United States, residing at Auburn, Cayuga county, New York, have invented certain new and useful Improvements in Internal-Combustion Motors, of which. the following is a full, clear, and ex act description.

My invention relates to internal combustion motors of the two-stroke cycle valveless type having a difi'erential piston in which the functions of an exhaust valve and of an inlet or scavenging valve are performed by the opening and closing of orts by the movement of a differential wor ing piston, said-ports being located in the proper position in the cylinder wall and in a tubular extension of the said difierential piston respectively.

Among the main objects of the invention are simplicity,compactness, convenience of construction, fewness of parts, increased eficiency of scavenging, and an arrangement of parts whereby the stresses of the various parts of the motor are more suited to the materials of which they are usually composed than now exists in motors ofthe ordinary construction of this general class.

In the accompanying drawings: Figure 1 is a longitudinal section of the cylinder end of a motor showing conventionally only such parts as are essential to a full understanding of the invention. Fig. 2 is a corresponding view of a modification.

In Fig. 1, represents the working cylinder. I represents-the large part of a differential working piston, while B represents the smaller part-or tubular extension of said piston. A suitable connection may be provided between the piston and a crank shaft (not shown), for example, an ordinary connecting rod X. The exhaust ports are shown at E. The inlet orscavengingports are shown at S as leading from the interior of the piston extension B into the cylinder C when the piston stands in one. position. The scavenging pump is formed by a scavenging piston A mounted upon the iston extension R and by a cylinder T in which the scavenging piston moves, which cylinder is of larger diameter than the working cylinder and may be conveniently formed'as an extension of the working barrel of the cylinder C enlarged or preferably of its water jacket wall W. The scavenging pum cylinder T has an inlet or suction va ve I,

which may be either automatically or posi tively operated, as desired. It is preferable however to connect the pump cylinder T with the portsS through the passage orpassages V leading to the interior of the piston extension R. v In this case, the clearance space within the scavenging pump cylinder T should be made large enough, as com pared with the displacement of the piston A, to keep the scavenging pressure down to the desired amount u on the opening of the ports. The ports perform the dual function of discharge passages for the scavenging pump cylinder T and air admission passages for the main cylinder C. By thus doing away with a separate air reservoir for holding a supply of scavenging air, higher initial scavenging pressure can be secured with the same amount of work performed in the scavenging pump cylinder T, although this pressure will rapidly fall away upon the opening of the ports S. This falllng away, however, is not objectionable in this particular instance because the scavenging of the cylinder C is done in a very short space of time, and the chief thing to-be accomplished is to provide a sufliciently high pressure of scavenging air at the beginning of the scavenging operation, to overcome the inertia of the gases to be expelled from the cylinder in a short time. When these gases are once in motion, a rapidly falling pressure will not affect unfavorably the scavenging function. K represents a fuel injection inlet. I i

In the modification shown in Fig. 2, I show the same arrangement of parts as in Fig. 1, excepting that the position of the.

working cylinder C and the scavenging cylinder, are reversed, bringing the scavenging pump nearer'to the crankshaft end of the motor. In this view 1' represents a tension rod that may pass through the interior of the piston P and its extension R, if desired. X represents the connecting rod, in this instance connected to the tension rod 1 and pivoted adjacent the scavenging pumpen'd of the tubular extension of the working piston. A repre sents .the scavenging pump piston and T represents the scavenging pump cylinder. In this arrangement, the scavenging pump piston A serves as a cross head for the connecting rod X and possesses advantages over the trunk form of main piston shown in Fig. 1, wherein the sidethrust due'to the type of motor in securing a superior distribution of strains. The running parts which, aside from the working piston, are usually and preferably made very light and of some material of great tensile strength,

are subject only to tension, for which, in view of their slenderness and great strength, they are much better adapted for than for compression stresses. The frame of the motor, on the other hand, which is usually and preferably made of cast iron, in this arrangement is subject only to compression stresses, to which, by reason of the character of the material and the large moment of inertia of its cross section, it is best adapted.

In the ordinary motor of the usual type it is usual and customary, in order to avoid an objectionable piston rod stufiing box in the cylinder, that the running parts be-always in compression and the frame always in tension, although owing to the materials of which they are usually made, they are respectively poorly suited to such stresses. The proposed arrangement shown in Fig. 2 involves a very much lighter and cheaper construction, as well as a smoother running construction, by reason of the better adaptation of the form and material of the frame and running parts to the stresses to which they are respectively subjected.

In the operation of the motor as shown in Fig. 1, the piston P is shown at the end of its working stroke. The exhaust port E is open, as is also the inlet port S. The cylinder C has been emptied of its burned gases by the discharge of the contents of the scavenging cylinder T through passage V, tubular extension R, and ports S, which latter open directly into the main cylinder C so as to permit the latter to be filled with a charge of fresh air. Upon the beginning of the return stroke of the piston, the ports S and E are closed and valve I opened, admitting air into the pump cylinder T. On the said return stroke, the air in the work ing cylinder C is compressed. At about the beginning of the working stroke, fuel may be injected through the inlet K and ignited by any suitable means, preferably by compression, whereby the burning of the fuel will cause internal expansion, forcing the piston P forwardly on its working stroke. During the latter part of the working stroke, the burned charge continues to expand doing work. On this working stroke the-suction valve 1 is closed so that when said stroke is completed to the extent of opening the valves S and E, the compressed air in the scavenging pump cylinder inlet ports E as shown are preferably so ar-,

ranged or proportioned that they will open slightly in advance of the opening of the portsS into the working cylinder C. It will be observed that the cylinder C has a head portion which is contracted and suitably proportioned to guide the piston extension R, the usual packing rings such as provided in engines of this internal combustion variety being provided wherever such devices may be employed with good efiect, there being no novelty claimed in the use of such devices in the present case. For convenience of expression we will refer to the arrangement of the working cylinder and the pump cylinder and their respective pistons as being a tandem arrangement.

What I claim is:

1. In an internal combustion motor of the high compression fuel burning type, a working cylinder, a differential piston arranged to reciprocate in said cylinder, the

smaller part of said piston comprising a tu bular extension, a fuel injection inlet .in said cylinder, a scavenging pump cylinder arranged in tandem with the working cyle inder, a scavenging pump piston carried by the tubular extension ofthe working piston and movingin said pump cylinder, an air inlet valve in communication with the scavenging pump cylinder, an air passage leading from the scavenging pump cylinder through the tubular extension and into the working cylinder including ports in the side of the tubular extension arranged to open' into the Working piston cylinder when the piston is near the end of its working stroke, an exhaust port in the Wall of the working cylinder arranged to be opened and closed by the larger part of the working piston when the latter is-near the end of its working stroke, and a connecting rod connected with said working piston, said fuel injection inlet being in the end of said working cylinder which is adjacent to said pump cylinder. v

2. In an internal combustion motor of the high compression fuel burning type, a working cylinder, a difierential piston arranged to reciprocate in said cylinder, the smaller part of said piston comprising atubular extension, a fuel injection inlet in said cylinder, a scavengmg pump cylinder arranged in tandem w1th the workmg cylinder, a

scavenging pump piston carried by the tubular extension of the working piston and moving in said pump, cylinder the working surfaces of said pistons facing toward one another, an air inlet valve in communication with the scavenging pump cylinder,' an air passage leading from the scavenging pump cylinder through the tubular extension and into the working cylinder including ports in the side of the tubular extension arranged to open into the working piston cylinder when the piston is near the end of its working stroke, an exhaust port in the wall of the working cylinder arranged to be opened and closed by the larger part of the working piston when the latter is near the end of its working "stroke, and. a connecting rod connected with said working pistonand pivoted adjacent the end of the tubular extension of the said working piston upon which the JAMES ALWARD SEYMOUR.

Witnesses:

E. E. Morse, IDA M. HUNZIKERT. 

